U.S. patent number 10,718,418 [Application Number 15/986,317] was granted by the patent office on 2020-07-21 for integrated drive generator having a variable input speed and constant output frequency and method of driving.
This patent grant is currently assigned to HAMILTON SUNSTRAND CORPORATION. The grantee listed for this patent is Hamilton Sundstrand Corporation. Invention is credited to Andrew P. Grosskopf, Glenn C. Lemmers, Jr..
United States Patent |
10,718,418 |
Grosskopf , et al. |
July 21, 2020 |
Integrated drive generator having a variable input speed and
constant output frequency and method of driving
Abstract
A method of driving an integrated drive generator is provided.
The method includes driving a carrier shaft of an epicyclic
differential and a variable component of a hydraulic trimming
device that is operably coupled to a sun gear of the epicyclic
differential. The method also includes driving a generator with an
output ring gear that is maintained at a constant output frequency.
The method further includes maintaining the constant output
frequency by controllably manipulating the speed of the sun gear
that is in operable communication with the output ring gear.
Inventors: |
Grosskopf; Andrew P. (Rockford,
IL), Lemmers, Jr.; Glenn C. (Loves Park, IL) |
Applicant: |
Name |
City |
State |
Country |
Type |
Hamilton Sundstrand Corporation |
Charlotte |
NC |
US |
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Assignee: |
HAMILTON SUNSTRAND CORPORATION
(Charlotte, NC)
|
Family
ID: |
48226980 |
Appl.
No.: |
15/986,317 |
Filed: |
May 22, 2018 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20180266532 A1 |
Sep 20, 2018 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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13457002 |
Apr 26, 2012 |
9989138 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H02K
7/10 (20130101); F16H 47/04 (20130101); H02K
7/116 (20130101); H02K 2213/09 (20130101); F16H
2037/088 (20130101) |
Current International
Class: |
F16H
47/04 (20060101); H02K 7/10 (20060101); H02K
7/116 (20060101); F16H 37/08 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1479943 |
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Nov 2004 |
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EP |
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8707785 |
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Dec 1987 |
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WO |
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Other References
Search Report regarding related EP App. No. 13165271.1; dated Jun.
1, 2017; 7 pgs. cited by applicant.
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Primary Examiner: Hansen; Colby M
Attorney, Agent or Firm: Cantor Colburn LLP
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a divisional application of, and claims
priority to, U.S. patent application Ser. No. 13/457,002, filed
Apr. 26, 2012, which is incorporated herein by reference in its
entirety.
Claims
What is claimed is:
1. A method of driving an integrated drive generator comprising:
driving a carrier shaft of an epicyclic differential and a variable
component of a hydraulic trimming device that is operably coupled
to a sun gear of the epicyclic differential; driving a generator
with an output ring gear that is maintained at a constant output
frequency; and maintaining the constant output frequency by
controllably manipulating the speed of the sun gear that is in
operable communication with the output ring gear.
2. The method of claim 1, further comprising driving the carrier
shaft of the epicyclic differential with an input shaft of a prime
mover and driving the output ring gear with the sun gear.
3. The method of claim 2, wherein the epicyclic differential
operates in a first condition, a second condition and a third
condition.
4. The method of claim 3, wherein the first condition comprises a
straight through speed, wherein the input shaft drives the carrier
shaft at a speed capable of driving the output ring gear at a
predetermined speed when the sun gear is at zero speed.
5. The method of claim 3, wherein the second condition comprises a
below straight through speed, wherein the sun gear drives the
planet gears at a ring gear speed equal to the predetermined speed,
wherein the sun gear is turning in an opposite direction of the
carrier gear.
6. The method of claim 5, further comprising increasing the ring
gear speed to the predetermined speed, wherein the hydraulic speed
trimming device increases a sun gear speed, wherein the sun gear is
turning in the direction of the carrier gear.
7. The method of claim 3, wherein the third condition comprises an
above straight through speed, wherein the sun gear drives the
planet gears at a resulting ring gear speed equal to the
predetermined speed.
8. The method of claim 7, further comprising decreasing the output
ring gear speed to the predetermined speed, wherein the hydraulic
speed trimming device manipulates the sun gear.
Description
BACKGROUND
Exemplary embodiments disclosed herein pertain to the art of an
integrated drive generator and, more particularly, to driving the
integrated drive generator at a constant output frequency with a
variable input speed.
Typically, integrated drive generators comprise a generator, a
differential and a hydraulic speed trimming device, with each
component requiring at least one major centerline for packaging.
The generator and the differential each require one centerline,
while the hydraulic trimming device requires from one to three
centerlines. Providing each component with at least one centerline
poses packaging issues for applications offering a restricted
amount of space, such as an aircraft, for example. Additionally,
such a configuration leads to undesirable weight and overhang
moments for the overall integrated drive generator assembly.
BRIEF DESCRIPTION
Disclosed is a method of driving an integrated drive generator is
provided. The method includes driving a carrier shaft of an
epicyclic differential and a variable component of a hydraulic
speed trimming device that is operably coupled to a sun gear of the
epicyclic differential. Also included is driving a generator with
an output ring gear that is maintained at a constant output speed.
Further included is maintaining the constant output frequency by
controllably manipulating the speed of the sun gear that is in
operable communication with the output ring gear.
BRIEF DESCRIPTION OF THE DRAWINGS
The following descriptions should not be considered limiting in any
way. With reference to the accompanying drawings, like elements are
numbered alike:
FIG. 1 is a cross-sectional view of an integrated drive
generator;
FIG. 2 is a cross-sectional view of a hydraulic trimming device and
an epicyclic differential of the integrated drive generator;
FIG. 3 is a cross-sectional view of the epicyclic differential;
and
FIG. 4 is a flow diagram illustrating a method of driving the
integrated drive generator.
DETAILED DESCRIPTION
A detailed description of one or more embodiments of the disclosed
apparatus and method are presented herein by way of exemplification
and not limitation with reference to the Figures.
The term "about" is intended to include the degree of error
associated with measurement of the particular quantity based upon
the equipment available at the time of filing the application.
The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
the present disclosure. As used herein, the singular forms "a",
"an" and "the" are intended to include the plural forms as well,
unless the context clearly indicates otherwise. It will be further
understood that the terms "comprises" and/or "comprising," when
used in this specification, specify the presence of stated
features, integers, steps, operations, elements, and/or components,
but do not preclude the presence or addition of one or more other
features, integers, steps, operations, element components, and/or
groups thereof.
Referring to FIGS. 1 and 2, an integrated drive generator (IDG) is
illustrated and generally referred to with numeral 10. The IDG 10
may be used in a variety of applications, with one such application
being an aircraft, for example. The IDG 10 is configured to receive
rotational energy on the input shaft 200 at varying rotational
(e.g., input) speeds from a prime mover (not illustrated) and
produce output electricity with a constant frequency. The IDG 10
comprises three major components disposed within a housing 12.
Specifically, IDG 10 includes: a generator 14, a hydraulic speed
trimming device 16 and an epicyclic differential 18 are disposed
within the housing 12.
The generator 14 produces an electrical output having a constant
output frequency, such as 3-phase 115 VAC at 400 Hz. In order to
produce the output with a constant frequency, the generator 14
spins at a constant speed. The hydraulic speed trimming device 16
is disposed proximate to the generator 14 and hydro-mechanically
regulates the speed of rotational energy provided to the generator
14. In particular, regardless of variations in the rotation speed
of prime mover, the hydraulic speed trimming device 16 is
configured to provide rotational energy that adds or subtracts
speed through the epicyclic differential 18 to the input shaft 200
so that the generator 14 speed is constant. In one embodiment, the
hydraulic speed trimming device 16 comprises a variable
displacement side and a fixed displacement side axial piston pump
and motor combination. The variable side is driven by a shaft 47
that is coupled to a carrier shaft 28 of the epicyclic differential
18.
The epicyclic differential 18 is operably coupled to the hydraulic
speed trimming device 16 and forms a gear relationship with the
generator 14 and the input shaft 200, as described in detail below.
Each of the generator 14, the hydraulic speed trimming device 16
and the epicyclic differential 18 include, and are disposed about,
a first centerline 20, a second centerline 22 and a third
centerline 24, respectively. The input shaft 200 in this
illustration is on another centerline 202. However, the input shaft
200 could also be packaged on various other centerlines in
alternative embodiments. In the illustrated embodiment, the third
centerline 24 of the epicyclic differential 18 corresponds to the
second centerline 22 of the hydraulic speed trimming device 16,
such that the epicyclic differential 18 and the hydraulic speed
trimming device 16 are relatively co-axially aligned. Although
illustrated and described in the aforementioned configuration, it
is contemplated that the third centerline 24 corresponds to the
first centerline 20, such that the epicyclic differential 18 and
the generator 14 are relatively co-axially aligned. The precise
configuration will be dictated by the packaging constraints imposed
by the specific application in which the IDG 10 is employed and it
is to be appreciated that the configurations described above
provide packaging flexibility and the ability to more compactly
arrange the components of the IDG 10.
Referring now to FIGS. 2 and 3, the epicyclic differential 18
includes an input gear 26 that is coupled to an output shaft of the
prime mover. This could be accomplished by using an input shaft 200
to the input gear 26. The input gear 26 transmits power to drive
the carrier shaft 28 of the epicyclic differential 18, with the
carrier shaft 28 driving a ring gear 30. The carrier shaft 28 is
also coupled to the variable side of the hydraulic speed trimming
device 16 by the shaft 47 or other type of coupling. The epicyclic
differential 18 is disposed on bearings 34 within the housing 12
and is mounted therein. Additionally, the epicyclic differential 18
includes at least three planet gears 36 and a sun gear 38 that work
in conjunction with the hydraulic speed trimming device 16 to
maintain the constant output speed of the ring gear 30, and
consequently the constant output frequency of the generator 14. The
three planet gears 36 mesh with the ring gear 30, as well as the
sun gear 38 The planet gears 36 are supported by carbon journal
bearings 50. The carbon journal bearings 50 allow for low or zero
speed operation of the planet gears 36 while they are loaded, as
well as high speed operation. The carbon journal bearings 50
require minimal oil for cooling and lubrication. Lubrication is
provided by passages 205 that are supplied by passages in the
carrier shaft 28. The bores of the journal bearings 50 are match
machined (line bored) to the carrier shaft 28. This provides
accurate location and perpendicularity for the planet gears 36
which in turn locate the sun gear 38. If the planet gears 36 were
not accurately located, the sun gear 38 could have excessive
movement or float and would have excessive wear that could lead to
premature failure. The carrier shaft bearing races 206 are also
match machined. This aids in locating the ring gear 30 so that the
planet gears 36 are not caused to shift off location and result in
premature wear. The sun gear 38 is axially located within the
carrier shaft 28 by thrust washers 207. The thrust washers 207
provide a bearing surface for the sun gear 38 to prevent wear, but
also allows some axial movement of the sun gear 38 within the
carrier shaft 28. The male splines on the shaft 44 also are
crowned. This allows the sun gear 38 to float and not be bound by
the shaft 44 or resulting torsional loads when transmitting
power.
As described above, the hydraulic speed trimming device 16 is
operably coupled to the epicyclic differential 18 and comprises a
fixed displacement side 40, as well as a variable displacement side
42. The fixed displacement side 40 is operably coupled to the sun
gear 38 of the epicyclic differential 18 via a splined coupling 44,
which is connected to a fixed block 45 of the hydraulic trimming
device 16, while the variable displacement side 42 is operably
coupled to the carrier shaft 28 of the epicyclic differential 18
via a splined shaft 47. The prime mover is thus also operably
connected to a variable component of the hydraulic trimming device
16 because the carrier shaft 28 is coupled to the prime mover by
the input shaft 200.
In operation, the epicyclic differential 18 operates at various
conditions based on the varying input speed generated by the prime
mover. Specifically, a "straight through" speed occurs when the
speed of the carrier shaft 28 is such that the ring gear 32 is
driven at a ring gear speed corresponding to the predetermined
speed and capable of driving the generator 14 at the desired output
frequency. In such a condition, the hydraulic trimming device 16
fixes the sun gear 38 speed to zero rpm and the input shaft 200
coupled to the generator at a predetermined gear ratio to maintain
a desired output frequency. A second condition is described as a
"below straight through" speed, where the varying input speed is
driving the carrier shaft 28 at a speed such that the ring gear 32
is driven at a ring gear speed lower than the predetermined speed
(if the sun gear 38 were held in fixed or non-rotating position)
and not capable of driving the generator 14 such that it produces
electricity at the constant output frequency. In such a condition,
the sun gear 38 must increase in speed to drive the ring gear 30 at
the predetermined speed. Speed is added by rotating the sun gear 38
opposite of the rotation of the carrier shaft 28. This is achieved
by adding speed to the sun gear 38 via the hydraulic speed trimming
device 16, where the variable displacement side 42 of the hydraulic
speed trimming device 16 is the pump and the fixed displacement
side 40 is the motor. The third condition is described as an "above
straight through" speed, where the varying input speed is driving
the carrier shaft 28 at a speed such that the ring gear 32 is
driven at a ring gear speed greater than the predetermined speed
(if the sun gear 38 were held in fixed or non-rotating position)
and driving the generator 14 at a frequency greater than the
constant output frequency. In such a condition, the sun gear 38
must decrease in speed to drive the ring gear 30 at the
predetermined speed. Speed is subtracted by rotating the sun gear
38 in the same direction of rotation as the carrier shaft 28. This
is achieved by decreasing the speed of the sun gear 38 and/or
switching the direction of rotation of the sun gear 38 (compared to
below straight through speed), where the variable displacement side
42 of the hydraulic trimming device 16 is the motor and the fixed
displacement side 40 is the pump.
Referring now to FIG. 4, a method of driving 100 the IDG 10 is also
provided. The IDG 10 has been previously described and specific
structural components need not be described in further detail. The
method of driving 100 includes driving a carrier shaft and a
variable side of a hydraulic speed trimming device with an input
shaft 102. The generator 14 is driven 104 by the ring gear 30 and
the fixed side of a hydraulic speed trimming device at a constant
output frequency that is to be maintained by controllably
manipulating 106 the carrier shaft 28, which is in operable
communication with the sun gear 38. Maintaining the constant output
frequency is accomplished by providing a corrective action 108 in
response to operation of the epicyclic differential 18 input shaft
speeds within a desired speed range.
Accordingly, the overall configuration of the IDG 10 provides
flexible and compact packaging options by reducing the number of
component centerlines, while maintaining robust component
interfaces that do not compromise IDG 10 operation.
While the present disclosure has been described with reference to
an exemplary embodiment or embodiments, it will be understood by
those skilled in the art that various changes may be made and
equivalents may be substituted for elements thereof without
departing from the scope of the present disclosure. In addition,
many modifications may be made to adapt a particular situation or
material to the teachings of the present disclosure without
departing from the essential scope thereof. Therefore, it is
intended that the present disclosure not be limited to the
particular embodiment disclosed as the best mode contemplated for
carrying out this present disclosure, but that the present
disclosure will include all embodiments falling within the scope of
the claims.
* * * * *